Vibrio vulnificus induces the death of a major bacterial species in the mouse gut via cyclo-Phe-Pro

Background A foodborne pathogen, Vibrio vulnificus, encounters normal microflora inhabiting the gut environments prior to causing fatal septicemia or gastroenteritis and should overcome the barriers derived from the gut commensals for successful infection. Its interactions with gut commensals during the infection process, however, have not yet been understood. In the present study, the effect of V. vulnificus on the community structures of gut microbiota in mice was examined. Results Analyses of microbiota in the fecal samples of mice that died due to V. vulnificus infection revealed the decreased abundance of bacteria belonged to Bacteroidetes, notably, the species Bacteroides vulgatus. In vitro coculturing of the two bacterial species resulted in the decreased survival of B. vulgatus. The antagonistic effect of V. vulnificus against B. vulgatus was found to be mediated by cyclo-Phe-Pro (cFP), one of the major compounds secreted by V. vulnificus. cFP-treated B. vulgatus showed collapsed cellular morphology with an undulated cell surface, enlarged periplasmic space, and lysed membranes, suggesting the occurrence of membrane disruption. The degree of membrane disruption caused by cFP was dependent upon the cellular levels of ObgE in B. vulgatus. Recombinant ObgE exhibited a high affinity to cFP at a 1:1 ratio. When mice were orally injected with cFP, their feces contained significantly reduced B. vulgatus levels, and their susceptibility to V. vulnificus infection was considerably increased. Conclusions This study demonstrates that V. vulnificus-derived cFP modulates the abundance of the predominant species among gut commensals, which made V. vulnificus increase its pathogenicity in the hosts.

TolCV1 Has Multifaceted Roles During Vibrio vulnificus Infection

RtxA1 is a major cytotoxin of Vibrio vulnificus (V. vulnificus) causing fatal septicemia and necrotic wound infections. Our previous work has shown that RpoS regulates the expression and secretion of V. vulnificus RtxA1 toxin. This study was conducted to further investigate the potential mechanisms of RpoS on RtxA1 secretion. First, V. vulnificus TolCV1 and TolCV2 proteins, two Escherichia coli TolC homologs, were measured at various time points by Western blotting. The expression of TolCV1 was increased time-dependently, whereas that of TolCV2 was decreased. Expression of both TolCV1 and TolCV2 was significantly downregulated in an rpoS deletion mutation. Subsequently, we explored the roles of TolCV1 and TolCV2 in V. vulnificus pathogenesis. Western blot analysis showed that RtxA1 toxin was exported by TolCV1, not TolCV2, which was consistent with the cytotoxicity results. Furthermore, the expression of TolCV1 and TolCV2 was increased after treatment of the host signal bile salt and the growth of tolCV1 mutant was totally abolished in the presence of bile salt. A tolCV1 mutation resulted in significant reduction of V. vulnificus induced-virulence in mice. Taken together, TolCV1 plays key roles in RtxA1 secretion, bile salt resistance, and mice lethality of V. vulnificus, suggesting that TolCV1 could be an attractive target for the design of new medicines to treat V. vulnificus infections.

Enhance Effectiveness of Moringa Leaves with Staphylococcus Epidermidis Bacteria

Plants are a source of various types of medicinal chemical compounds, one of which is as an anti-infection where the use of natural plant-based ingredients (herbs) is again a trend among Indonesians. Cleanliness is very important because of the increasing number of diseases that arise due to bacteria and germs. The skin is the part that covers the surface of the body and has the main function of protecting it from various kinds of disturbances and external stimuli. Moringa leaves are natural ingredients that have antibacterial potential. Moringa (Moringa oleifera, Lamk) is a plant that has antibacterial benefits. Staphylococcus Epidermidis is a bacterium that causes various pyogenic and skin infections, separation, abscess formation, and fatal septicemia. This study aims to test the antibacterial activity of Moringa leaves against Staphylococcus Epidermidis. The method used in the extraction of Moringa leaves is maceration using ethanol as a solvent. As for testing, it is known that the moringa leaf extract has antibacterial activity against Staphylococcus Epidermidis at concentrations of 5%, 10%, 20%, 40%, and 80% and the minimum inhibitory content (MIC) is 12 mm in Staphylococcus Epidermidis. The difference in the concentration of Moringa leaf extract influenced the inhibition of the growth of Staphylococcus Epidermidis bacteria.

Neisseria meningitidis Induced Fatal Waterhouse–Friderichsen Syndrome in a Patient Presenting With Disseminated Intravascular Coagulation and Multiple Organ Failure

Neisseria meningitidis-induced acute systemic meningococcal disease is an emergency and a fatal condition that has a high mortality rate. In patients with a fulminant infection, a maculopapular petechial eruption, purpura fulminans, or an ecchymotic lesion are worrisome signs reflecting disseminated intravascular coagulation (DIC) and hint at Waterhouse–Friderichsen syndrome (WFS). Here, we describe a rare case of a patient with a fulminant Neisseria meningitidis-induced acute systemic meningococcal disease presenting with high-grade fever without meningitis symptoms. Fatal septicemia with DIC and multiple organ failure was noted. WFS was chiefly suspected. We highlight the clinical features and pathogenesis of Neisseria meningitidis-induced meningococcemia and WFS. We propose that they should be kept in mind, especially in patients presenting with a petechial eruption and purpura fulminans.

Whole-Genome Sequences and Classification of Streptococcus agalactiae Strains Isolated from Laboratory-Reared Long-Evans Rats (Rattus norvegicus)

ABSTRACT In collaboration with the CDC’s Streptococcus Laboratory, we report here the whole-genome sequences of seven Streptococcus agalactiae bacteria isolated from laboratory-reared Long-Evans rats. Four of the S. agalactiae isolates were associated with morbidity accompanied by endocarditis, metritis, and fatal septicemia, providing an opportunity for comparative genomic analysis of this opportunistic pathogen.